INTERNATIONAL JOURNAL OF AGRICULTURE & BIOLOGY ISSN Print: 1560–8530; ISSN Online: 1814–9596 20–1578/2021/25–5–955–961 DOI: 10.17957/IJAB/15.1751 http://www.fspublishers.org Full Length Article To cite this paper: Ahmed HM, M Ashfaq, T Mukhtar, MA Khan (2021). Categorization of available cucumber genotypes against Zucchini Yellow Mosaic Virus and root-knot nematode (Meloidogyne incognita). Intl J Agric Biol 25:955‒961 Categorization of Available Cucumber Genotypes against Zucchini Yellow Mosaic Virus and Root-Knot Nematode (Meloidogyne incognita) Hira Manzoor Ahmed 1* , Muhammad Ashfaq 1 , Tariq Mukhtar 1 and Muhammad Azam Khan 2 1 Department of Plant Pathology, Pir Mehr Ali Shah Arid Agriculture University Rawalpindi, Pakistan 2 Department of Horticulture, Pir Mehr Ali Shah Arid Arid Agriculture University Rawalpindi, Pakistan * For correspondence: hirabajwa30@gmail.com Received 02 November 2020; Accepted 13 March 2021; Published 16 April 2021 Abstract In the present study, fifteen cucumber genotypes were screened against Zucchini yellow mosaic virus (ZYMV) and root-knot nematode (Meloidogyne incognita) individually and in combinations. All the cucumber genotypes behaved differently regarding root and shoot lengths and weights, number of galls, eggmasses and ZYMV infection when inoculated with M. incognita and ZYMV alone and in combinations. None of the fifteen cucumber genotypes was found immune, highly or moderately resistant to M. incognita. Two genotypes viz., Alpha Prime and Patio were found resistant to the nematode. Contrarily, Max Pack and Beti-alpha were highly susceptible as evident by maximum galls on their roots and reductions in growth variables. Similarly, the genotypes Best PIC, Songrooh, Northern Pack, C-7 and C-5 appeared as moderately susceptible whereas Shaheen, Jakson, C-1, C-2, C-3 and C-9 genotypes showed susceptible reactions to the nematode alone. Similar trend was noticed when the genotypes were inoculated with both the nematode and the virus. Similarly, on the basis of disease rating scale, two genotypes viz., Alpha Prime and Patio were grouped as moderately resistant to ZYMV. On the other hand, eleven genotypes viz., Max Pack, Shaheen, Songrooh, Northern Pack, Jakson, Beti-alpha, C-1, C-2, C-3, C-5 and C-9 were catalogued as highly resistant while two genotypes Best PIC and C-7 were categorized as susceptible against ZYMV alone. Similarly, all the genotypes behaved in the same way when inoculated with M. incognita. Two genotypes Alpha Prime and Patio were found resistant against both the pathogens inoculated simultaneously and hence are recommended for cultivation. © 2021 Friends Science Publishers Keywords: Galls; Resistance; Root-knot nematode; Varietal screening; ZYMV Introduction Cucumber (Cucumis sativus L.) is a significant seasonal vegetable which belongs to crop family of Cucurbitaceae. It is a clambering trailing plant that yields tube-shaped fruits which are mostly used in domestic cuisines. The crop is fourth in line for significance after tomatoes, cabbage and onions in Asia, while second to tomato in Europe. China was the first in yielding 60% produce in 2018, chased by Iran, Turkey and Russia. Cucumber is cultivated over 3367 hectares with yearly produce of 68664 tons in Pakistan (FAO 2019). It is cultivated on large scale; however, its production is seriously threatened by mosaic viruses and root-knot nematodes (Ashfaq et al. 2017; Ahsan et al. 2020). Root-knot nematodes (RKN) have extensive host range and infest various seasonal and perennials (Mukhtar and Kayani 2019; Nazir et al. 2019). Approximately 90% of the horticultural crops-producing areas are infested with RKN (Trudgill et al. 2000; Tariq-Khan et al. 2017a; Mukhtar and Kayani 2020). There are more than 100 described species of RKN in which Meloidogyne incognita and M. javanica are commonly prevailing in tropics and subtropical zones of the globe including Pakistan (Trudgill et al. 2000; Mukhtar et al. 2017). A similar dominance of these two species has also been reported for Pakistan, with 52% M. incognita and 31% M. javanica, 8% M. arenaria, 7% M. hapla and 2% other RKN species (Tariq-Khan et al. 2017b; Kayani et al. 2018). For okra grown in the central Punjab province of Pakistan, RKN incidences were 74.7% for M. incognita, 24.0% for M. javanica, 1.6% for M. arenaria and 0.8% for M. hapla (Kayani and Mukhtar 2018; Hussain and Mukhtar 2019), respectively. Similarly, cucumber grown in the Pothowar region of the Punjab province, Pakistan, was found to be infested by 78% by M. incognita, 19% by M. javanica, 2% by M. arenaria and 1% by M. hapla (Kayani et al. 2013; Azeem et al. 2021). From Pakistan, five RKN species have been reported so far from tropical and cooler areas. The first three species have also been found infecting vegetables in the Western Himalayan region of Azad Jammu and Kashmir (Khan et al. 2020). Furthermore, these nematodes develop disease complexes with soil borne fungal and bacterial pathogens causing vascular wilts and